Integers were used in the 15th century by European traders to label barrels of grain or flour. For example, a barrel that was 1 pound too heavy was labeled +1, and a barrel that was 1 pound too light was labeled –1.

A trader checked twenty 50-pound barrels and found the labels to be: five –3s, nine –5s, two +4s, and four –8s. Find the actual total weight of the barrels.​